uh, leave them unlocked? or were you in the bad part of Idaho?
It didn't matter if I left them unlocked or not. The mechanism itself would freeze and I couldn't open the door until I warmed the inner workings with the hot key. Also, although it wasn't a "bad" part of Idaho, there were the usual numbers of druggies and such that would steal what they could to sell for drugs. So I usually locked up my house and my car.
Bad part of Idaho...LOL...I can't imagine that.
In Chicago, we lock our doors for good reason. ;)